/*
Copyright 2011 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package com.google.rsm.core;

/**
 * A interface for all events handled by the state machine system.
 *
 * @author arunabhaghosh@google.com (Arunabha Ghosh)
 */
public interface Event {
  /**
   * Every event is represented by a type.  The implementation must
   * return an object that is unique for the event type.  This object
   * must implement {@code #hashCode}, {@code #equals}, etc.,
   * correctly.
   *
   * <p>The state machine framework uses the {@code EventType} to
   * determine whether it should handle an event.
   *
   * @return an object identifying the type of this event
   */
  EventType getType();
}
